T1 L3: Blood volume and its regulation by the kidney

Cards (42)

  • What components of blood are central to blood volume setting in the kidney?
    sodium, water
  • Formed elements (RBCs, WBCs, plasma) do not contribute directly to blood pressure.
  • Three ways to increase blood pressure?
    1. high blood volume
    2. vasoconstriction
    3. high cardiac output
  • Fluid entering all Bowman's capsules?
    Glomerular Filtration Rate
  • Diagnostic tests for kidney function?
    1. Blood urea nitrogen (BUN)
    2. Serum creatinine
    3. B-type natriuretic peptide (BNP)
  • Which test measures urea, waste product of protein digestion, produced by the liver, and hence measuring if it is removed correctly by the kidneys?
    blood urea nitrogen (BUN)
  • What is high BUN caused by?
    low GFR
  • Along with low GFR, what can high BUN levels indicate?
    kidney failure, CHF, hypovolaemia
  • What do high levels of serum creatinine indicate?
    low GFR
  • Which hormone directly decreases diuresis?
    Antidiuretic hormone (ADH, vasopressin)
  • What is ADH secreted from?
    posterior pituitary gland
  • Effect of decreased diuresis on blood pressure?
    increased blood pressure
  • What is loss of plasma fluid into urine called?
    diuresis
  • How do diuretic drugs work?
    antagonise antidiuretic hormones, leading to fluid loss
  • Steroid hormone that increases plasma fluid?
    aldosterone
  • What kind of hormone is aldosterone?
    mineralocorticoid
  • What is aldosterone secreted by?
    adrenal cortex
  • How does aldosterone increase plasma fluid?
    aldosterone ➝ kidneys ➝ reabsorb more NaClwater follows salt ➝ reabsorb more waterdecrease diuresis by decreasing natriuresis
  • Hormone that increases blood pressure?
    angiotensin II
  • How does angiotensin increase blood pressure?
    • causes vasoconstriction
    • increases fluid retention by:
    • increasing aldosterone secretion by adrenal cortex (more blood volume)
    • increasing ADH secretion by posterior pituitary (antidiuretic)
  • Hormone that contributes to ventricular hypertrophy + cardiac remodelling?
    angiotensin II
  • What system regulates blood pressure and volume?
    Renin-Angiotensin-Aldosterone System (RAAS)
  • Renin-Angiotensin-Aldosterone System mechanism?
    angiotensinogen produced by liver ➝ activated by RENIN enzyme (made in kidneys) ➝ becomes angiotensin I ➝ activated by ACE enzyme (made in lungs) ➝ becomes angiotensin II ➝ activates aldosterone
  • Cytokine/hormone that derives erythropoiesis?
    Erythropoietin (EPO)
  • Where is EPO made?
    kidney
  • What is EPO made in the liver in response to?
    hypoxia in kidney
  • What peptide hormone reduces fluid overload?
    B-type Natriuretic Peptide (BNP)
  • What is B-type Natriuretic Peptide (BNP) secreted by?
    ventricular cardiomyocytes
  • What is B-type Natriuretic Peptide (BNP) secreted in response to?
    increased preload (diastolic stretching) and volume overload
  • How does B-type Natriuretic Peptide (BNP) work?
    increases natriuresis ➝ increased GFR ➝ increase diuresis ➝ decrease venous pressure and systemic peripheral vascular resistance
  • Elevated levels of which hormone indicates heart failure?
    B-type Natriuretic Peptide (BNP)
  • What does congestion inside hepatic portal system cause?
    ascites
  • Fluid build up in abdomen?
    ascites
  • 2 ways kidney acid-base balance fails?
    • kidney failure (glomerulus doesn't filter)
    • renal tubular failure (tubules don't get rid of acid)
  • Low GFR, high creatinine & BUN, metabolic acidosis, high anion gap, high BP, low urine, oedema, need to urinate more esp at night?
    Acute kidney injury / uremic kidney failure
  • Normal GFR, metabolic acidosis, normal anion gap, low blood K+, non-anion gap hyperchloremic metabolic acidosis?
    Renal tubule failure
  • Example of thiazide like diuretic?
    indapamide
  • Type of diuretics that work by blocking reabsorption at DCT?
    thiazide like
  • Type of diuretics that work by blocking reabsorption in thick loop?
    loop
  • Example of a loop diuretic?
    furosemide